It is the objective to purify prostaglandin dehydrogenase (PGDH) to homogeneity, to characterize the catalytic and chemical properties of the molecule and to use the enzyme as an analytical tool in a sensitive enzymatic fluorimetric assay of total prostaglandins in tissues and body fluids. Another objective of the proposed project is to design quantitative histo- and cytochemical methods for studying the distribution of PGDH at the histological or even cellular level.